Pd-catalyzed cross-coupling of alkynylsilanols with iodobenzenes
摘要:
Alkynylsilanols were efficiently coupled with iodobenzene derivatives by a Pd catalyst ill the presence of TBAF, and the corresponding substituted alkynes could be obtained in good to excellent yields. (C) 2001 Elsevier Science Ltd. All rights reserved.
annulation of readily available benzoicacids and alkynes is reported for the first time. The carboxylate group acts as both a directing group and an internal nucleophilic reagent to facilitate a C(sp2)–H vinylation/annulation cascade. This reaction avoids the classically oxidative [4+2] annulation, allowing the efficient synthesis of a wide array of eight-membered lactones under oxidant-free conditions
two‐carbon (C2) cyclization buildingblock. The present protocol successfully inhibits the competitive cycloaddition with the C≡N bond of acetonitrile, but enables the in situ formation of an unsaturated carbon–carbonbond and the subsequent cycloaddition as a C2 unit. This chemistry features simple reaction conditions, high chemoselectivities, wide substrate scope, and offers a new and practical approach
A copper-catalyzedhighlyregio- and stereospecific selenosulfonation of alkynes with arylsulfonohydrazides and diphenyl diselenide has been developed. This novel three component reaction proceeds under very mild conditions and with a broad scope of substrates, providing a wide range of (E)-β-selenovinyl sulfones in good to excellent yields.
A facile and efficient copper-catalyzed azidative multifunctionalization of alkynes has been developed by using N-fluorobenzenesulfonimide (NFSI) as both nitrogensource and arylsource and trimethylsilyl azide (TMSN3) as azido source. This transformation proceeds under mild conditions, providing a series of α-azido-α-aryl imine in good yields by a single operation starting from a wide range of alkynes